US9830671B2 - Power management system, power management method, and network server - Google Patents

Abstract

A power management system comprises a plurality of HEMSs10 and CEMSs40. The CEMS40 receives, from each HEMS10, power information including the amount of power consumed by a load connected to each HEMS10. The CEMS40 transmits, to each HEMS10, reduction information including the amount of power that should be reduced in each consumer, in response to a curtailment signal and the power information.

Description

TECHNICAL FIELD

The present invention relates to a power management system, a power management method, and a network server that reduce power consumed by a load provided in a plurality of consumers.

BACKGROUND ART

In recent years, it is known a technology of controlling, by a power management apparatus (for example, HEMS: Home Energy Management System) provided in each consumer, a load provided in a consumer and a dispersed power source provided in a consumer, for example.

Examples of the dispersed power source may include a power generation equipment that utilizes clean energy such as sunlight, wind power, and geothermal energy. Alternatively, examples of the dispersed power source may also include a fuel cell such as SOFC (Solid Oxide Fuel Cell).

In such a system, when it is expected that an amount of power to be supplied from a power grid is smaller than a total amount of power consumed in a consumer connected to the power grid, a power company that manages the power grid transmits, to each power management apparatus, a power curtailment signal (DR: Demand Response) instructing restraint of an amount of power consumed, and each power management apparatus reduces power consumed by a load in response to the power curtailment signal (for example, Patent Literature 1). The power curtailment signal is a signal indicating an amount of power that should be reduced by each consumer (for example, a ratio of power to be reduced relative to power currently consumed, or an absolute value of power to be reduced relative to power currently consumed).

CITATION LISTPatent Literature

Patent Literature 1: Japanese Patent Application Publication 2010-128810

SUMMARY OF THE INVENTION

In this case, from a viewpoint of a power company, it may suffice that the total amount of power consumed is reduced irrespective of an amount of power reduced by each consumer connected to the power grid. However, there is a need of considering situations of a plurality of consumers (power management apparatus).

Therefore, the present invention has been achieved in order to solve the above-described problem, and an object thereof is to provide a power management system, a power management method, and a network server with which it is possible to appropriately restrain an amount of power consumed by a load provided in each consumer.

A power management system according to the first feature comprises a plurality of power management apparatuses each of which is provided in each of a plurality of consumers and a network server connected to the plurality of power management apparatuses via a network. Each power management apparatus transmits, to the network server, power information including the amount of power consumed by a load connected to each power management apparatus and a curtailment signal transmitted from a power company that manages a power grid. The network server transmits, to each power management apparatus, reduction information including the amount of power that should be reduced in each consumer, in response to the curtailment signal and the power information.

In the first feature, each power management apparatus transmits, to the network server, the power information including an amount of power consumed for each category to which the load connected to each power management apparatus belongs.

In the first feature, each power management apparatus reduces power consumed by the load connected to each power management apparatus, in response to the reduction information received from the network server.

In the first feature, the curtailment signal includes the amount of power that should be reduced from an amount of power currently consumed by the load connected to the power grid.

In the first feature, the category has a priority, and the network server decides the amount of power that should be reduced in each consumer so as to preferentially reduce power consumed by a load belonging to a category having a lower priority.

In the first feature, the network server decides the amount of power that should be reduced in each consumer, in accordance with a coefficient corresponding to a contract of a maximum current value available for each consumer.

A power management method according to the second feature is applied to a power management system comprising a plurality of power management apparatuses each of which is provided in each of a plurality of consumers and a network server that manages the plurality of power management apparatuses. The power management method comprises: a step of transmitting, from each power management apparatus to the network server, power information including the amount of power consumed by a load connected to each power management apparatus and a curtailment signal transmitted from a power company that manages a power grid; and a step of transmitting, from the network server to each power management apparatus, reduction information including the amount of power that should be reduced in each consumer, in response to the curtailment signal and the power information. The curtailment signal includes the amount of power that should be reduced from an amount of power currently consumed by a load connected to the power grid.

In the second feature, in the step of transmitting the power information and the curtailment signal, the power information including an amount of power consumed for each category to which the load connected to each power management apparatus belongs is transmitted from each power management apparatus to the network server.

In the second feature, the power management method further comprises a step of reducing, in each power management apparatus, power consumed by the load connected to each power management apparatus, in response to the reduction information received from the network server.

A network server according to the third feature is connected to a plurality of power management apparatuses each of which is provided in each of a plurality of consumers via a network. The network server comprises: a reception unit that receives, from each power management apparatus, power information including the amount of power consumed by a load connected to each power management apparatus and a curtailment signal transmitted from a power company that manages a power grid; and a transmission unit that transmits, to each power management apparatus, reduction information including the amount of power that should be reduced in each consumer, in response to the curtailment signal and the power information transmitted from the power company that manages the power grid.

In the third feature, the reception unit receives, from each power management apparatus, the power information including an amount of power consumed for each category to which the load connected to each power management apparatus belongs.

In the third feature, the curtailment signal includes the amount of power that should be reduced from an amount of power currently consumed by the load connected to the power grid.

The present invention can provide a power management system, a power management method, and a network server with which it is possible to appropriately restrain an amount of power consumed by a load provided in each consumer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing apower management system100 according to the first embodiment.

FIG. 2 is a diagram showing apower management system100 according to the first embodiment.

FIG. 3 is a block diagram showing theHEMS10 according to the first embodiment.

FIG. 4 is a block diagram showing thenetwork server20 according to the first embodiment.

FIG. 5 is a sequence diagram showing a power management method according to the first embodiment.

FIG. 6 is a sequence diagram showing a power management method according to the first modification.

DESCRIPTION OF THE EMBODIMENT

Hereinafter, the power management system according to the embodiment of the present invention will be described. Note that the same or similar reference signs are applied to the same or similar portions in the following descriptions of the drawings.

It must be understood that the drawings are schematic, and the ratio of each dimension and the like may differ from the real one. Accordingly, specific dimensions and the like should be understood with reference to the following description. Furthermore, it must be understood that, the relationship or ratio of dimensions included in each of the drawings may differ.

[Summary of the Embodiment]

A power management system according to the embodiment comprises a plurality of power management apparatuses each of which is provided in each of a plurality of consumers and a network server connected to the plurality of power management apparatuses via a network. Each power management apparatus transmits, to the network server, power information including the amount of power consumed by a load connected to each power management apparatus and a curtailment signal transmitted from a power company that manages a power grid. The network server transmits, to each power management apparatus, reduction information including the amount of power that should be reduced in each consumer, in response to the curtailment signal and the power information.

Thus, the network server connected to the plurality of power management apparatuses via a network instructs each power management apparatus to reduce power, thereby making it possible to appropriately restrain the amount of power consumed by the load provided in each consumer.

[First Embodiment]

(Configuration of Power Management System)

Hereinafter, a power management system according to a first embodiment will be described.FIG. 1 andFIG. 2 are a diagram showing apower management system100 according to the first embodiment.

Firstly, as shown inFIG. 1, thepower management system100 includes an HEMS10, a group ofloads20, asmart meter30, aCEMS40, agrid50, and apower company60. The HEMS10 and the group ofloads20 are provided within aconsumer70.

The HEMS10 is an apparatus (HEMS: Home Energy Management System) that manages power of theconsumer70. In the first embodiment, the HEMS10 includes a function of controlling the group ofloads20 by using a protocol such as ECHONET Lite or ZigBee. For example, the HEMS10 is capable of controlling the power consumed by the group ofloads20 by controlling an operation mode of the group ofloads20.

In the first embodiment, as the HEMS10, an HEMS10A₁an HEMS10A₂, an HEMS10B₁, and an HEMS10B₂are provided. Further, the HEMS10 is an example of a power management apparatus. The HEMS10 will be described in detail later (seeFIG. 3).

The group ofloads20 is a group of equipment by which power is consumed. Examples of the group ofloads20 include equipment such as a refrigerator, lighting, an air conditioner, and TV. Further, a dispersed power source such as a storage battery, a photovoltaic power generation equipment (PV), and a fuel cell (SOFC) may be provided within theconsumer70.

In this case, it is possible to classify a load included in the group of loads20 (that is, a load connected to the HEMS10) into a plurality of categories. Further, each category has a priority.

For example, the load is classified into three categories (categories A to C). The category A is a category to which a load (for example, a refrigerator), for example, indispensable in a daily life, belongs. The category B is a load (for example, lighting and an air conditioner) directly related to a daily life, other than loads belonging to the category A. The category C is a load (for example, TV) not belonging to the category A nor the category B. In this case, the category A has the highest priority, and the category C has the lowest priority.

The category is basically set previously to each load; however, the category is preferably changeable by a user. For example, even when a category of a certain load is set as the category C at the time of product shipment, it is preferable that the category be changeable to another category depending on each usage manner of a user. TheHEMS10 stores information notifying the category to which the load belongs, periodically received from each load included in the group ofloads20, for example. Alternatively, when a category of a load included in the group ofloads20 is changed (for example, when a new load is added to the group ofloads20, or when the category of the load is changed), theHEMS10 receives the information for notifying the change in category from the load and stores the information.

In the first embodiment, as the group ofloads20, a group of loads20A₁, a group of loads20A₂, a group of loads20B₁, and a group of loads20B₂are provided. The HEMS10A₁and the group of loads20A₁are provided within a consumer70A₁, and the HEMS10A₂and the group of loads20A₂are provided within a consumer70A₂. Likewise, the HEMS10B₁and the group of loads20B₁are provided within a consumer70B₁, and the HEMS10B₂and the group of loads20B₂are provided within a consumer70B₂.

Basically, thesmart meter30 is a meter that measures power consumed by the group of loads20. In the first embodiment, thesmart meter30 includes a communication function, and is capable of receiving information from theHEMS10, theCEMS40, and the grid50 (power company60).

In the first embodiment, as thesmart meter30, a smart meter30A₁, a smart meter30A₂, and asmart meter30B are provided. As shown inFIG. 1, thesmart meter30 may be provided closer to thegrid50 than theCEMS40, or may be provided closer to theconsumer70 than theCEMS40.

TheCEMS40 is an apparatus (CEMS: Community Energy Management System) that manages a plurality ofHEMSs10. TheCEMS40 collects information from eachHEMS10 and provides instructions for an operation to eachHEMS10.

In the first embodiment, as theCEMS40, aCEMS40A and aCEMS40B are provided. Further, theCEMS40 is an example of a power management apparatus.

Thegrid50 is a power line for supplying eachconsumer70 with power supplied from a power station, etc. Thepower company60 is a business operator managing thegrid50.

Theconsumer70 is a unit managed by oneHEMS10. For example, theconsumer70 may be a single house or a housing complex such as an apartment house. Alternatively, theconsumer70 may be a dwelling unit configuring a housing complex.

Secondly, as shown inFIG. 2, thepower management system100 has anetwork server200. Thenetwork server200 is connected to the plurality of power management apparatuses (theHEMSs10 and the CEMSs40) via anetwork300. Further, thenetwork server200 is connected to thepower company60 via thenetwork300. Thenetwork300 is, for example, an Internet network. Details of thenetwork server200 will be given below (seeFIG. 4).

(Power Management Apparatus)

Hereinafter, a power management apparatus according to the first embodiment will be described.FIG. 3 is a block diagram showing the HEMS10 (an example of the power management apparatus) according to the first embodiment. As shown inFIG. 3, theHEMS10 has areception unit11, atransmission unit12, and acontrol unit13.

Thereception unit11 receives various information from thenetwork server200 and thepower company60. Firstly, thereception unit11 receives, from thepower company60, a power curtailment signal (DR; Demand Response) instructing restraint of the amount of power consumed. Secondly, thereception unit11 receives, from thenetwork server200, reduction information including the amount of power that should be reduced in eachconsumer70. In this case, it should be noted that the reduction information includes the amount of power to be reduced for each category.

Thetransmission unit12 transmits various information to thenetwork server200. Firstly, thetransmission unit12 transmits, to thenetwork server200, the power curtailment signal (DR; Demand Response) received from thepower company60.

Secondly, thetransmission unit12 transmits, to thenetwork server200, classification result information (power information) including an amount of power consumed for each category to which a load connected to the HEMS10 (a load included in the group of loads20) belongs. In this case, the amount of power consumed included in the classification result information may be the amount of power that can be reduced for each category.

The amount of power that can be reduced for each category may be a numerical value manually input by a user, or a numerical value calculated by theHEMS10 on the basis of a use history of a load stored in theHEMS10. Alternatively, when a dispersed power source is provided within theconsumer70, the amount of power that can be reduced for each category may include not only the amount of power reduced by an operation suspension of a load but also the amount of power reduced that is achieved when the power supply from thegrid50 is reduced as a result of the group ofloads20 being supplied with output power from the dispersed power source.

Thirdly, thetransmission unit12 transmits, to thenetwork server200, reduced amount information indicating the amount of power reduced in accordance with the reduction information.

Thecontrol unit13 comprehensively controls theHEMS10. Thecontrol unit13 controls the group ofloads20 connected to theHEMS10 by using a signal that complies with a protocol such as ECHONET Lite or ZigBee. In particular, thecontrol unit13 is capable of controlling the power consumed by the group ofloads20 by controlling an operation mode of the group of loads20. Specifically, thecontrol unit13 transmits, to the load included in the group ofloads20, a signal for switching to an operation mode in which it is possible to reduce the power consumed, in response to the reduction information received from theCEMS40.

In this case, thecontrol unit13 grasps a category to which the load included in the group ofloads20 belongs. Further, thecontrol unit13 grasps power consumed by the load (power currently consumed) included in the group of loads20.

When the dispersed power source is provided within theconsumer70, thecontrol unit13 grasps output power from the dispersed power source. Accordingly, when the power consumed by the group ofloads20 is reduced, thecontrol unit13 may not only stop the operation of the load but also replace at least a part of the power supplied to the group ofloads20 with the output power from the dispersed power source.

(Network Server)

Hereinafter, a network server according to the first embodiment will be described.FIG. 4 is a block diagram showing thenetwork server200 according to the first embodiment. As shown inFIG. 4, thenetwork server200 has areception unit210, atransmission unit220, and acontrol unit230.

Thereception unit210 receives various information from theHEMS10. Firstly, thereception unit210 receives, from eachHEMS10, the power curtailment signal (DR; Demand Response) instructing restraint of the amount of power consumed. It should be noted that an amount to be reduced designated by the power curtailment signal is the amount of power that should be reduced in eachconsumers70.

Secondly, thereception unit210 receives, from eachHEMS10, the classification result information including the amount of power consumed for each category to which the load connected to the HEMS10 (the load included in the group of loads20) belongs.

Thirdly, thereception unit210 receives, from eachHEMS10, the reduced amount information indicating the amount of power reduced in accordance with the reduction information.

Thetransmission unit220 transmits various information to theHEMS10 and thepower company60. Firstly, thetransmission unit220 transmits, to eachHEMS10, the reduction information including the amount of power that should be reduced in eachconsumer70. As described above, it should be noted that the reduction information includes the amount of power to be reduced for each category.

Secondly, thetransmission unit220 transmits, to thepower company60, the reduced amount information received from eachHEMS10.

Thecontrol unit230 comprehensively controls theCEMS40. Firstly, thecontrol unit230 determines whether or not power curtailment designated by the power curtailment signal is achieved, in response to the classification result information received from eachHEMS10. In particular, thecontrol unit230 determines whether or not the power curtailment is achieved by reduction in power consumed by the load in order from a category having a lower priority.

Secondly, thecontrol unit230 allocates the amount of power that should be reduced in eachconsumer70 according to the classification result information including the amount of power consumed for each category.

For example, an amount of power to be reduced R(i) that should be reduced in a consumer (i), or HEMS (i), is calculated according to the following procedure, for example. In this case, as a category to which a load belongs, a case where the categories A to C exist is provided as an example.

Firstly, in a case where the power curtailment is achieved by reduction in power consumed by the load belonging to the category C, the amount of power to be reduced R (i) is calculated by the following Equation (1).
R(i)=P_C(i)×c(i)×PDR/P_CSUM
wherein
ΣP_C(i)×c(i)=P_CSUM, andPDR≦P_CSUM  Equation (1)

In this case, P_C(i) denotes an amount of power that can be reduced (amount of power included in the classification result information) for a load belonging to the category C at the consumer (i). PDR denotes an amount of power to be reduced designated by the power curtailment signal, and specifically, denotes an amount of power that should be reduced in a whole of the plurality ofconsumers70 provided under theCEMS40. P_CSUM is a sum of the amount of power that can be reduced for the load belonging to the category C, in a whole of the plurality ofconsumers70 provided under theCEMS40.

c(i) is a coefficient corresponding to a contract of a maximum current value available for the consumer (i). Preferably, the greater the contracted maximum current value is, the greater a value of c(i) is. It is noted that c(i) may be a constant value (for example, “1”).

Secondly, in a case where the power curtailment is achieved by reduction in power consumed by the load belonging to the category C and the category B, the amount of power to be reduced R(i) is calculated by the following Equation (2).
R(i)=P_C(i)+P_B(i)×b(i)×(PDR−P_BSUM)/P_BSUM
wherein
ΣP_B(i)×b(i)=P_BSUM, andPDR≦P_CSUM+P_BSUM  Equation (2)

In this case, P_B(i) denotes an amount of power that can be reduced (amount of power included in the classification result information) for a load belonging to the category B at the consumer (i). P_BSUM is a sum of the amount of power that can be reduced for the load belonging to the category B, in a whole of the plurality ofconsumers70 provided under theCEMS40.

b(i) is a coefficient corresponding to a contract of a maximum current value available for the consumer (i). Preferably, the greater the contracted maximum current value is, the greater a value of b(i) is. It is noted that b(i) may be a constant value (for example, “1”). Further, b(i) may be the same in value as c(i), or may be different in value from c(i).

Thirdly, in a case where the power curtailment is not achieved by reduction in power consumed by the load belonging to the category C and the category B, the amount of power to be reduced R(i) is calculated by the following Equation (3).
R(i)=P_C(i)+P_B(i)+P_A(i)×a(i)×(PDR−P_CSUM−P_BSUM)/P_ASUM
wherein
ΣP_A(i)×a(i)=P_ASUM, andP_CSUM+P_BSUM<PDR  Equation (3)

In this case, P_A(i) denotes an amount of power that can be reduced (amount of power included in the classification result information) for a load belonging to the category A at the consumer (i). P_ASUM is a sum of the amount of power that can be reduced for the load belonging to the category A, in a whole of the plurality ofconsumers70 provided under theCEMS40.

a(i) is a coefficient corresponding to a contract of a maximum current value available for the consumer (i). Preferably, the greater the contracted maximum current value is, the greater a value of a(i) is. It is noted that a(i) may be a constant value (for example, “1”). Further, a(i) may be the same in value as c(i) or b(i), or may be different in value from c(i) or b(i).

(Power Management Method)

Hereinafter, the power management method according to the first embodiment will be described.FIG. 5 is a sequence diagram showing an operation of thepower management system100 according to the first embodiment.

As shown inFIG. 5, instep10₁, eachHEMS10 transmits, to each group ofloads20, a load information request for requesting the power consumed by the load (the power currently consumed) included in the group of loads20.

Instep20₁, eachHEMS10 receives, from the group ofloads20, load information including the power consumed by the load included in the group of loads20 (the power currently consumed). In this case, it should be noted that the load information includes the amount of power consumed for each category.

Instep30₁, thenetwork server200 receives, from eachHEMS10, the classification result information including the amount of power consumed for each category to which the load connected to the HEMS10 (the load included in the group of loads20) belongs.

In this case, it is noted that processes ofstep10₂to step30₂are similar to the processes ofstep10₁to step30₁. That is, thenetwork server200 periodically receives the classification result information from eachHEMS10.

Instep40, eachHEMS10 receives, from thepower company60, the power curtailment signal (DR; Demand Response) instructing restraint of the amount of power consumed.

Instep50, thenetwork server200 receives, from eachHEMS10, the power curtailment signal (DR; Demand Response).

Instep60, thenetwork server200 allocates the amount of power that should be reduced in eachconsumer70, in accordance with the classification result information including the amount of power consumed for each category.

For example, in a case where the power curtailment is achieved by reduction in the power consumed by the load belonging to the category C (that is, in a case where PDR≦P_CSUM is satisfied), the amount of power to be reduced R(i) is calculated by the following Equation (1).
R(i)=P_C(i)×c(i)×PDR/P_CSUM
wherein
ΣP_C(i)×c(i)=P_CSUM  Equation (1)

In a case where the power curtailment is achieved by reduction in the power consumed by the load belonging to the category C and the category B (that is, in a case where PDR≦P_CSUM+P_BSUM is satisfied), the amount of power to be reduced R(i) is calculated by the following Equation (2).
R(i)=P_C(i)+P_B(i)×b(i)×(PDR−P_CSUM)/P_BSUM
wherein
ΣP_B(i)×b(i)=P_BSUM  Equation (2)

In a case where the power curtailment is not achieved by reduction in the power consumed by the load belonging to the category C and the category B (that is, in a case where P_CSUM+P_BSUM<PDR is satisfied), the amount of power to be reduced R(i) is calculated by the following Equation (3).
R(i)=P_C(i)+P_B(i)+P_A(i)×a(i)×(PDR−P_CSUM−P_BSUM)/P_ASUM
wherein
ΣP_A(i)×a(i)=P_ASUM  Equation (3)

Instep70, thenetwork server200 transmits, to eachHEMS10, the reduction information including the amount of power that should be reduced in eachconsumer70. It should be noted that the reduction information includes the amount of power to be reduced for each category.

Instep80, eachHEMS10 reduces the power consumed by the load included in the group ofloads20, in response to the reduction information received from thenetwork server200.

Instep90, thenetwork server200 receives, from eachHEMS10, the reduced amount information indicating the amount of power reduced in accordance with the reduction information.

Instep100, thenetwork server200 transmits, to thepower company60, the reduced amount information received from eachHEMS10.

In the first embodiment, thenetwork server200 connected to the plurality ofHEMSs10 via thenetwork300 transmits the reduction information to eachHEMS10, in response to the classification result information received for each category having a priority.

The amount of power that can be reduced depends on each consumer. Further, some consumers usually try to save power, and other consumers do not usually try to save power. Thus, when reduction in power consumed is requested uniformly to consumers, the sense of unfairness arises among the consumers. Thus, thenetwork server200 connected to the plurality ofHEMSs10 via thenetwork300 allocates the amount of power to be reduced in eachconsumer70 in consideration of the amount of power that should be reduced in a whole of theconsumers70 and the amount of power that can be reduced for eachconsumer70, and it is thus possible to restrain a senses of unfairness among the respective consumers.

On the other hand, thepower company60 does not need to consider the amount of power that can be reduced for eachconsumer70, and may just designate, to theHEMS10, the amount of power that should be reduced in eachconsumer70. That is, thepower company60 does not need power usage information of eachconsumer70, and thus, thepower company60 does not need to bear a burden required for managing the power usage information of eachconsumer70, either. It is not necessary for theconsumer70 to provide thepower company60 with power usage information of theconsumer70, either, which is preferable in view of privacy protection.

If it is difficult to achieve a target amount to be reduced (for example, 10%), then thepower company60 may transmit a power curtailment signal indicating a larger amount to be reduced (for example, 15%) to reduce total power currently consumed by the target amount to be reduced in a whole of the plurality ofconsumers70. However, because of allocating the amount of power to be reduced, that is, the amount that can be reduced for eachconsumer70, thenetwork server200 is capable of highly certainly achieving the target amount to be reduced. Thus, thepower company60 does not also need to increase the amount to be reduced designated by the power curtailment signal to be larger than the target amount to be reduced.

As described above, according to thepower management system100 of the embodiment, it is possible to appropriately restrain the amount of power consumed by the load provided in each consumer.

Further, the reduction information is transmitted in response to the classification result information including the amount of power consumed for each category having a priority, and thus, power consumed by a load belonging to a category having a lower priority is reduced first in an orderly manner. As a result, reduction in power that should be supplied to a load belonging to a category having a higher priority, that is, a load necessary for a daily life, is restrained.

(First Modification)

A description will be given below of a first modification of the first embodiment. Differences from the first embodiment are mainly described, below.

In the first embodiment, thenetwork server200 directly transmits the reduction information to eachHEMS10. On the other hand, in the first modification, thenetwork server200 transmits the reduction information to theCEMS40.

In particular, in the first modification, thenetwork server200 allocates the amount of power that should be reduced in eachconsumer70 provided under eachCEMS40, in accordance with the classification result information including the amount of power consumed for each category.

EachCEMS40 may allocate the amount of power that should be reduced in eachconsumer70. In such a case, thenetwork server200 allocates the amount of power to be reduced for eachCEMS40. In other words, thenetwork server200 allocates, to eachCEMS40, the total amount of power that should be reduced at theconsumers70 provided under theCEMS40, and entrusts eachCEMS40 to allocate the amount of power that should be reduced in eachconsumer70.

(Power Management Method)

Hereinafter, a power management method according to the first modification will be described.FIG. 6 is a sequence diagram showing an operation of thepower management system100 according to the first modification. InFIG. 6, a description ofstep10₁to step50 shown inFIG. 5 is omitted to simplify explanation. Further, inFIG. 6, step160,step171, and step173 are provided in place ofstep60 and step70 compared with a sequence shown inFIG. 5.

As shown inFIG. 6, thenetwork server200 allocates the amount of power that should be reduced in eachconsumer70 provided under eachCEMS40, in accordance with the classification result information including the amount of power consumed for each category. The allocation of the amount of power to be reduced is basically similar to that of the first embodiment.

Further, as described above, thenetwork server200 may allocate, to eachCEMS40, the total amount of power that should be reduced at theconsumers70 provided under theCEMS40, and entrust eachCEMS40 to allocate the amount of power that should be reduced in eachconsumer70.

Instep171, thenetwork server200 transmits, to eachCEMS40, the reduction information including the amount of power that should be reduced at theconsumers70 provided under eachCEMS40. It should be noted that the reduction information includes the amount of power to be reduced for each category.

In step173, eachCEMS40 transmits, to theHEMS10, the reduction information including the amount of power that should be reduced in eachconsumer70, in response to the reduction information received from thenetwork server200.

[Other Embodiments]

The present invention has been described according to the aforementioned embodiment. It must not be understood that, however, the discussions and the drawings constituting apart of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

In the embodiment, theHEMS10 is employed as an example of the power management apparatus; however, the embodiment is not limited thereto. The power management apparatus may be theCEMS40. Alternatively, the power management apparatus may be a BEMS (Building and Energy Management System) or a FEMS (Factory Energy Management System), for example.

In the embodiment, thenetwork server200 periodically receives, from each consumer70 (HEMS10), the classification result information including the amount of power consumed for each category. However, the embodiment is not limited thereto. For example, thenetwork server200 may request each consumer70 (HEMS10) to transmit the classification result information in response to the power curtailment signal (DR; Demand Response).

Note that the entire content of the Japanese Patent Application No. 2011-209956 (filed on Sep. 26, 2011) is incorporated herein by reference.

INDUSTRIAL APPLICABILITY

The present invention can provide a power management system, a power management method, and a network server with which it is possible to appropriately restrain an amount of power consumed by a load provided in each consumer.

Claims (12)

The invention claimed is:

1. A power management system comprising:

a plurality of power management apparatuses each of which is provided in one of a plurality of consumers; and

a network server connected to the plurality of power management apparatuses via a network,

wherein each of the plurality of power management apparatuses comprises

a receiver configured to receive a curtailment signal directly from a power company that manages a power grid without being relayed by the network server, and

a transmitter configured to transmit the curtailment signal to the network server via the network,

wherein the network server comprises

a receiver configured to receive the curtailment signal relayed by each of the plurality of power management apparatuses, and

a transmitter configured to transmit, to each of the plurality of power management apparatuses, reduction information including an amount of power that should be reduced in each consumer, in response to the received curtailment signal, and

wherein each of the plurality of power management apparatuses is configured to reduce power consumed by a load connected to that power management apparatus, in response to the reduction information received from the network server.

2. The power management system according toclaim 1, wherein each of the plurality of power management apparatuses is configured to transmit, to the network server, power information including an amount of power consumed for each category to which the load connected to that power management apparatus belongs.

3. The power management system according toclaim 1, wherein the curtailment signal includes an amount of power that should be reduced from an amount of power currently consumed by loads connected to the plurality of power management apparatuses.

4. The power management system according toclaim 3, wherein each category has a priority, and the network server is configured to decide the amount of power that should be reduced in each consumer so as to preferentially reduce power consumed by a load belonging to a category having a lower priority.

5. The power management system according toclaim 3, wherein the network server is configured to decide the amount of power that should be reduced in each consumer, in accordance with a coefficient corresponding to a contract of a maximum current value available for each consumer.

6. The power management system according toclaim 1,

wherein each of the plurality of power management apparatuses is further configured to transmit, to the network server via the network, power information including the amount of power consumed by a load connected to that power management apparatus, in addition to the curtailment signal, and

wherein the network server is further configured to determine the amount of power that should be reduced in each consumer based on the power information received from the plurality of power management apparatuses.

7. A power management method applied to a power management system comprising a plurality of power management apparatuses, each of which is provided in one of a plurality of consumers, and a network server that manages the plurality of power management apparatuses, the method comprising:

receiving, by a receiver of each of the plurality of power management apparatuses, a curtailment signal directly from a power company that manages a power grid without being relayed by the network server;

transmitting, from a transmitter of each of the plurality of power management apparatuses to the network server, the curtailment signal;

receiving, by a receiver of the network server, the curtailment signal relayed by each of the plurality of power management apparatuses;

transmitting, from a transmitter of the network server to each of the plurality of power management apparatuses, reduction information including an amount of power that should be reduced in each consumer, in response to the received curtailment signal; and

reducing, in each of the plurality of power management apparatuses, power consumed by a load connected to that power management apparatus, in response to the reduction information received from the network server.

8. The power management method according toclaim 7, further comprising transmitting, from each of the plurality of power management apparatuses to the network server, power information including an amount of power consumed for each category to which a load connected to that power management apparatus belongs.

9. The power management method according toclaim 7, further comprising:

transmitting, from each of the plurality of power management apparatuses to the network server, power information including the amount of power consumed by a load connected to that power management apparatus, in addition to the curtailment signal; and

determining, by the network server, the amount of power that should be reduced in each consumer based on the power information received from the plurality of power management apparatuses.

10. A network server connected to a plurality of power management apparatuses, each of which is provided in one of a plurality of consumers via a network, the network server comprising:

a receiver configured to receive, from each of the plurality of power management apparatuses, a curtailment signal relayed by each power management apparatus received from a power company that manages a power grid; and

a transmitter configured to transmit, to each of the plurality of power management apparatuses, reduction information including an amount of power that should be reduced in each consumer, in response to the received curtailment signal, such that each power management apparatus responsively reduces power consumed by a load connected to that power management apparatus.

11. The network server according toclaim 10, wherein the receiver receives, from each of the plurality of power management apparatuses, power information including an amount of power consumed for each category to which the load connected to that power management apparatus belongs.

12. The network server according toclaim 11, wherein the curtailment signal includes an amount of power that should be reduced from an amount of power currently consumed by loads connected to the plurality of power management apparatuses.

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